Method and system for reporting a short message capability via an IP multimedia subsystem

ABSTRACT

A method and system for reporting short message (SM) capability over an IP multimedia subsystem (IMS) using a session initiation protocol (SIP) are disclosed. A wireless transmit/receive unit (WTRU) registers with a core network and sends a message indicating its SM capability via the IMS to the core network. The core network then updates the WTRU capabilities based on the message and routes an SM to the WTRU via the IMS.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. provisional application No.60/705,911 filed Aug. 5, 2005, which is incorporated by reference as iffully set forth.

FIELD OF INVENTION

The present invention is related to wireless communication systems. Moreparticularly, the present invention is related to a method and systemfor reporting short message (SM) capability via an IP multimediasubsystem (IMS).

BACKGROUND

At initiation of a wireless communication session between a wirelesstransmit/receive unit (WTRU) and a core network, the WTRU requests for asignaling connection in an attach procedure according to thirdgeneration partnership project (3GPP) standards. Currently, a networkcapability to support a short message service (SMS) via dedicatedchannels and global packet radio service (GPRS) channels are reported ina network capability information element (IE).

However, there is no means for reporting WTRU SM capability via an IMS.As a consequence, the core network is unaware of the WTRU SM capabilityand an SM may not be routed to the WTRU via an IMS. Since the currentwireless communication standards mandate that the WTRU indicate thepreferred mode of operation (in terms of delivery of SMS), the WTRUshould indicate the delivery of SMS over a GSM network or a GPRS basednetwork. However, for example, if the WTRU is operating on a GPRSnetwork and the preferred setting is on a GSM network, SMS messages maybe lost. The same problem also occurs when the WTRU operates in a GSMmode while the preferred operation is GPRS delivery. Therefore, it isdesirable to provide a means for the WTRU to report the SM capabilityover the IMS to the core network.

SUMMARY

The present invention is related to a method and system for reporting anSM capability over an IMS using a session initiation protocol (SIP). AWTRU registers with a core network and sends a message indicating its SMcapability via the IMS to the core network. The core network thenupdates the WTRU capabilities based on the message and routes an SM tothe WTRU via the IMS.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a wireless communication system thatsupports messaging services via an IMS in accordance with the presentinvention.

FIG. 2 is a flow diagram of a process for reporting the SM capability ofthe WTRU during an attach procedure in accordance with the presentinvention.

FIG. 3A shows a conventional network capability information element(IE).

FIG. 3B shows a network capability IE configured in accordance with thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

When referred to hereafter, the terminology “WTRU” includes but is notlimited to a user equipment (UE), a mobile station, a fixed or mobilesubscriber unit, a pager, or any other type of device capable ofoperating in a wireless environment.

The features of the present invention may be incorporated into anintegrated circuit (IC) or be configured in a circuit comprising amultitude of interconnecting components.

FIG. 1 shows a block diagram of a wireless communication system 100 thatsupports messaging services over an IMS 116 using an SIP in accordancewith the present invention. The system 100 includes a core network andone or more radio access networks (RANs) which may implement differentradio access technologies (RATs). The RANs include, but are not limitedto, a global standards for mobile communication (GSM) RAN 102, a thirdgeneration (3G) RAN 104 and an interworking wireless local area network(I-WLAN) 106. The core network includes a short message service (SMS)gateway mobile switching center (SMS-GMSC)/interworking mobile switchingcenter (IW-MSC) 120, a home location register (HLR) 122, a short messageIP gateway (SM-IP-GW) 118, a GPRS support node (GSN) 114, a mobileswitching center (MSC) 112, an IMS 116, and a visitor location register(VLR) 124.

The GSM RAN 102 is connected to the MSC 112 for circuit switchingservices and the 3G RAN 104 is connected to the GSN 114 for packetswitching services. The I-WLAN 106 has an IP access capability to theIMS 116, (via a packet data gateway (PDG) and/or a WLAN access gateway(WAG)), for IP services through the core network.

A service center 126 sends a short message (SM) 140 to theSMS-GMSC/IW-MSC 120. The SMS-GMSC/IW-MSC 120 is a gateway between theservice center 126 and the MSC 112, the GSN 114 and/or the SM-IP-GW 118.The SMS-GMSC/IW-MSC 120 accepts a WTRU-terminated SM or aWTRU-originated SM and delivers the SM 140 to the MSC 112, the GSN 114or the SM-IP-GW 118. When the WTRU 130 is connected to the 3G RAN 104,the SM 140 may be routed from the SMS-GMSC/IW-MSC 120 to the 3G RAN 104via the GSN 114. When the WTRU 130 is connected to the GSM RAN 102, theSM 140 may be routed from the SMS-GMSC/IW-MSC 120 to the GSM RAN 102 viathe MSC 112. When the WTRU 130 is registered with the SM-IP-GW 118, theSM 140 may be routed via the SM-IP-GW 118 and the IMS 116 using an SIP,which will be explained in detail hereinafter.

The SM 140 may be an SMS message, (e.g., text only or text plus videomessage), a multimedia message service (MMS) message, an instant messageservice message, or the like.

Before originating or receiving the SM 140 over an IP network, such asthe IMS 116, the WTRU 130 must register with an appropriate SM-IP-GW118. The SM-IP-GW 118 communicates between the WTRU 130 and theSMS-GMSC/IW-MSC 120, and provides protocol interworking for delivery ofthe SM 140 between the WTRU 130 and the SMS-GMAC/IW-MSC 120. TheSM-IP-GW 118 maintains a registration status of WTRUs 130. Uponregistration, the SM-IP-GW 118 informs the HLR 122 that the WTRU 130 hassuccessfully registered with the SM-IP-GW 118.

Upon receipt of the SM 140 from the service center 126, theSMS-GMSC/IW-MSC 120 interrogates the HLR 122 to retrieve routinginformation for the WTRU 130. When the WTRU 130 is connected to the GSMRAN 102 or the 3G RAN 104, the HLR 122 returns the address of the MSC112 or the GSN 114, respectively. If the WTRU 130 is registered with theSM-IP-GW 118, the HLR 122 returns the address of the SM-IP-GW 118.

In accordance with the present invention, the SM 140 is routed to theWTRU 130 over the IMS 116 using an SIP. The WTRU 130 is registered withthe SM-IP-GW 118 and the registration status is recorded in the HLR 122.When the SMS-GMSC/IW-MSC 120 interrogates the HLR 122 for routinginformation, the HLR 122 returns the address of SM-IP-GW 118, (ratherthan the address of an appropriate MSC 112 or SGSN 114), to theSMS-GMSC/IW-MSC 120. The SMS-GMSC/IW-MSC 120 then delivers the SM 140 tothe SM-IP-GW 118 using the obtained address of the SM-IP-GW 118. TheSM-IP-GW 118 then forwards the SM 140 to the IMS 116.

The IMS 116 then forwards the SM 140 either to the 3G RAN 104 via theGSN 114 or to the I-WLAN 106, depending on the current connection of theWTRU 130. When the WTRU 130 is connected to the 3G RAN 104, the SM 140is routed from the SM-IP-GW 118 to the 3G RAN 104 via the IMS 116 andthe GSN 114 using an SIP. When the WTRU 130 is connected to the I-WLAN106, the SM 140 is routed from the SM-IP-GW 118 to the I-WLAN 106 viathe IMS 116 using an SIP.

In accordance with the present invention, the WTRU 130 reports its SMcapability via an IMS using an SIP to the core network, (preferably aserving GPRS support node (SGSN)), to be recorded in the HLR 122. Thereporting is preferably performed during an attach procedure, which willbe described in detail hereinafter. The core network may also inform theWTRU 130 of the network's capability to support the SMS over an IMS.

FIG. 2 is a flow diagram of a process 200 for reporting WTRU SMcapabilities via an IMS in accordance with the present invention. TheWTRU 130 may be a multi-mode WTRU including multiple radio units forsupporting multiple RATs, such as a GSM air interface, an I-WLAN airinterface, a 3G air interface, or the like. Upon power up at step 202,the WTRU 130 sends a radio resource control (RRC) connection requestmessage to a radio network controller (RNC) 113 of a 3G RAN to establisha connection to the 3G RAN 104 (step 204). The RNC 113 performs anadmission control based on predetermined factors, such as availabilityof resources, or the like (step 206). If the RNC 113 decides to admitthe WTRU 130, the RNC 113 sends an RRC connection setup message to theWTRU 130 (step 208). The WTRU 130 then sends an RRC connection completemessage to the RNC 113 (step 210).

The WTRU 130 then sends an attach request message to the RNC 113 inorder to receive 3G services (step 212). In accordance with the presentinvention, the information regarding the SM capability of the WTRU viaan IMS is sent using a network capability IE along with the attachrequest message. The RNC 113 selects an SGSN 114 to serve the WTRU 130and forwards the attach request message to the selected SGSN 114 alongwith the SM capability information (step 214). Authentication andsecurity functions are performed between the WTRU 130 and the SGSN 114(step 216). Once the WTRU 130 is authenticated at step 218, the SGSN 114sends an update WTRU capability message to an HLR 122 to update WTRUcapabilities (step 220) and sends an attach accept message to the RNC113, which forwards it to the WTRU 130 (steps 222, 224). Once the WTRUcapability is updated at the HLR 122 and the WTRU 130 is registered withthe SM-IP-GW 118, the SM 140 may be routed to the WTRU 130 via the IMS116. The core network, (preferably an SGSN), may also send informationregarding the network's capability of supporting SMS data delivery overan IMS. The information may be sent along with the attach accept messageor any other message.

FIG. 3A shows a conventional network capability IE. The networkcapability IE includes information bits indicating an SM capability viadedicated channels and an SM capability via GPRS channels, but not an SMcapability via an IMS.

FIG. 3B shows an example of a network capability IE configured inaccordance with the present invention. The network capability IE shownin FIG. 3B includes new information bits 302 indicating the SMcapability via an IMS. The new information bits for the SM capabilityvia an IMS may indicate capability of supporting SMS, IMS, MMS, or thelike. A similar network capability IE may be used for the core networkto report the network's capability to support SMS via an IMS.

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone without the other features andelements of the preferred embodiments or in various combinations with orwithout other features and elements of the present invention.

1. A method for use in a wireless transmit/receive unit (WTRU), themethod comprising: the WTRU connecting to a radio access network (RAN);the WTRU registering with a core network via the RAN; the WTRU sending afirst message including a network capability information element (IE) tothe core network using session initiation protocol (SIP), the networkcapability indicating a capability of the WTRU to receive Short MessageService (SMS) messages via an Internet Protocol multimedia subsystem(IMS); and the WTRU receiving a SMS message via the IMS using SIP. 2.The method of claim 1 wherein the network capability IE indicatescapability of transmitting and receiving at least one of a SMS message,a multimedia message service (MMS) message, and an instant messageservice message via the IMS.
 3. The method of claim 1 furthercomprising: receiving a second message, the second message reporting acapability of the core network to support a SMS via the IMS.
 4. Themethod of claim 1 wherein the RAN is a third generation (3G) RAN.
 5. Themethod of claim 1 wherein the RAN is an interworking wireless local areanetwork (I-WLAN).
 6. A wireless transmit/receive unit (WTRU), the WTRUcomprising: a processor, configured to generate a first messageincluding a network capability information element (IE), the networkcapability IE indicating a capability of the WTRU to receive ShortMessage Service (SMS) via an Internet Protocol multimedia subsystem(IMS); a transmitter, configured to send the first message including thenetwork capability IE to a core network using session initiationprotocol (SIP) and to register the WTRU with the core network via aradio access network (RAN); and a receiver, configured to receive a SMSmessage via the IMS using SIP.
 7. The WTRU of claim 6 wherein the RAN isa third generation (3G) RAN.
 8. The WTRU of claim 6 wherein the RAN isan interworking wireless local area network (I-WLAN).
 9. The WTRU ofclaim 6 wherein the network capability IE indicates capability oftransmitting and receiving at least one of a SMS message, a multimediamessage service (MMS) message, and an instant message service messagevia the IMS.
 10. The WTRU of claim 6 wherein the receiver is furtherconfigured to receive a second message, the second message reporting acapability of the core network to support a SMS via the IMS.